package com.tm.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;


public class Md5 {

	private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
	
	public static String getMD5Str(String str) {  
	        MessageDigest messageDigest = null;  
	  
	        try {  
	            messageDigest = MessageDigest.getInstance("MD5");  
	  
	            messageDigest.reset();  
	  
	            messageDigest.update(str.getBytes("UTF-8"));  
	        } catch (NoSuchAlgorithmException e) {  
	            System.out.println("NoSuchAlgorithmException caught!");  
	            System.exit(-1);  
	        } catch (UnsupportedEncodingException e) {  
	            e.printStackTrace();  
	        }  
	  
	        byte[] byteArray = messageDigest.digest();  
	  
	        StringBuffer md5StrBuff = new StringBuffer();  
	  
	        for (int i = 0; i < byteArray.length; i++) {              
	            if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)  
	                md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i]));  
	            else  
	                md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));  
	        }  
	  
	        return md5StrBuff.toString();  
	    }  

	/**
	* 使用MD5对字符串进行MD5计算
	* @param str 需要加密的源字符串
	* @return 经过加密后的结果MD5码
	*/
	public  static String EncoderByMd5(String str) throws NoSuchAlgorithmException,UnsupportedEncodingException 
	{
		MessageDigest md5 = MessageDigest.getInstance("MD5");
		byte[] results = md5.digest(str.getBytes());
		String resultString = byteArrayToHexString(results);
		return resultString.toUpperCase();
	}

	/**
	* 使用MD5对字节数组进行摘要计算
	* @param src 需要加密的源字节数组
	* @return 经过加密后的结果MD5码
	*/
	public String MD5(byte[] src) throws NoSuchAlgorithmException,UnsupportedEncodingException
	{
		MessageDigest md5 = MessageDigest.getInstance("MD5");
	    byte[] results = md5.digest(src);
	    String resultString = byteArrayToHexString(results);
		return resultString.toUpperCase();
	}

	private static String byteArrayToHexString(byte[] b) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++) {
			resultSb.append(byteToHexString(b[i]));
		}
		return resultSb.toString();
	}


	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n = 256 + n;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

}
